P. maniculatus species group. Highly differentiated morphologically and allozymically from mainland P. maniculatus (Avise et al., 1974, 1979; Burt, 1932), though considered a derivative from a maniculatus like ancestor (Lawlor, 1983), a relationship supported by sequence data from several mitochondrial DNA genes (Hafner et al., 2001; Hogan et al., 1997). Banded karyotype described by Smith et al. (2000), who reported a unique heterochromatin addition in sejugis as compared with P. maniculatis and recommended retention of the former as species. Hafner et al. (2001:787), on the other hand, viewed the sequence divergence between the two as minimal and predicted that additional study "will demonstrate that P. sejugis should be included as a subspecies of P. maniculatus." Ultimate decision on its status will hinge upon a broader context of taxonomic inquiry that includes peninsular populations of P. maniculatus (coolidgei) and those along the northern Pacific coast (P. keeni), as noted by Hogan et al. (1997). See Alvarez-Castañeda (2001, Mammalian Species, 658).